The yeast Candida albicans is a normal resident of the human digestive tract. It is also the most common fungal pathogen of humans, causing both mucosal and systemic infections, particularly in immune compromised patients. This proposal seeks to understand how C. albicans orchestrates its many interactions with the host. Our strategy is to approach aspects of commensalism and pathogenicity through dissection of the transcriptional circuitry that controls these processes. Our overarching goal is to understand how C. albicans is specialized to thrive and cause disease in many different environments of the host.